Long Term Effects of Retarded Timing

[allyolds68]

I purchased a 97 Sea Ray Signature 210BR with a 5.7LX 4bbl a two years ago that was running terrible over 2500 rpm's. It only had 300 hours on it so I went through it pretty well before purchasing it and determined that it had good spark and compression so I could probably figure out what was ailing it. I changed plugs, wires, distributor cap and rebuilt the carb right off the bat and it improved greatly but still wasn't right. When it started I'd get a big puff of soot out. I ran a few cans of Sea foam through it which increased the amount of soot I'd get but still didn't make it quite right. A month or two after I bought it I checked the timing and found that it was set at zero degrees . When I attempted to rotate the distributor to advance it was bottomed out against a bracket. Turns out it looked like someone did some motor work to it, removed the intake manifold, and replaced the distributor one tooth off. I set the timing to 10 degrees and it runs like new. I still run Sea Foam through it a few times a year and didn't have any problems with it last year. I just want to make sure there isn't something else that I should do (short of tearing a good running motor apart). My oil pressure 40 psi under load and drops to 15-20 at idle when it's hot. That seems low to me but hasn't changed in the last two years. I cut the oil filter apart this year when I changed the oil and there's no bronze in there so I was happy about that. I don't know if the retarded timing would have effected that anyway.

Thoughts?

 

[achris]

Advance timing will do engine damage. Retarded timing will only do wallet damage. (By using more fuel than it ordinarily should)

 

[allyolds68]

Advance timing will do engine damage. Retarded timing will only do wallet damage. (By using more fuel than it ordinarily should)

Thanks!

In a Google search it seemed that retarded timing causes a motor to run hot. I'm guessing that in a raw water cooled boat that would be less of a problem.

I'll keep running a can or two if Sea Foam per season. I assume it can't hurt anything

 

[tpenfield]

I would not run the engine retarded too long, because it could spread to other parts of the boat, like a virus.

Glad you found the issue. Would not hurt to do a compression test at some point. But 10 degrees out is not the end of the world

 

[boatman37]

a small block chevy only needs 7 PSI oil pressure at idle and 10 PSI per 1000 RPM so it sounds like you are good to go

 

[gm280]

You should have noticed an increase in power once you advance the timing and it may be running a little hotter also. Retarded timing make an engine easier to start but hurts the output power range. An engine that runs at the perfect advance point before detonation starts is giving everything it can. JMHO

 

[bruceb58]

You should have noticed an increase in power once you advance the timing and it may be running a little hotter also.

It will run cooler with the timing advanced.

 

[tpenfield]

It will run cooler with the timing advanced.

+ 1 ^^^

Here is a graph that I found a while ago, showing how the power (peak cylinder pressure) goes down and exhaust temperature goes up in an engine as the timing is retarded.



As far as long term effect of not running at the desired timing . . . it may take a toll on the exhaust valves.

 

[allyolds68]

Thanks for all the replies. I was pretty sure there shouldn't be any long term effects but I wanted to bounce it off everyone to be sure. I have no idea how long the boat was running with zero degree timing. I'm the third owner and I have a feeling the guy I bought it from wasn't telling me the whole story about the boat. He had only owned it two or three years and I'll bet it never ran right the whole time he owned it. I found out from my local Mercruiser dealer that the boat originally had a Webber carb and that was switched out to a remanufactured Q-Jet. Something else must have gone wrong for them to pull the intake manifold with less than 300 hours on it. It could have been overheated, who knows. All I know is it's a very clean boat and it's running great now and I'm not going to mess with it anymore.

 

[gm280]

+ 1 ^^^

Here is a graph that I found a while ago, showing how the power (peak cylinder pressure) goes down and exhaust temperature goes up in an engine as the timing is retarded.



As far as long term effect of not running at the desired timing . . . it may take a toll on the exhaust valves.

Thanks for the correction. I was always under the impression that retarded timing ran cooler. Guess that is wrong! :facepalm:

 

[bruceb58]

Thanks for the correction.

You are welcome.

Engine is running less efficient and the heat/energy that is being generated is not going to push the pistons so it stays within the engine block itself.